However, Wongwanich et al.(1983, 1990) have published more complete accounts of the Palae- ozoic stratigraphy in Satun Province, based on successions in Tarutao Island and the adjacent mainland, from which a better picture of the re- gional stratigraphy can be gained.This succes- sion provides the principal factual base on which to hang our biogeographical assessment herein.